Just one, but it hurt.
A lovely green Fisher Hoo-Koo-E-Koo, my first 'serious' bike.
The scumbag broke into my shed in Harlesden, and somehow managed to get the bike, still shackled to a set of steel shelves, over a 6' wall.
The next night, he came back (presumably for my Dawes), only to be defeated by the much improved shed door security. So he broke into the flat downstairs instead, only to be chased away by a fearless Italian lady armed with an umbrella.
The police took that quite seriously, and set up camp in my kitchen the next three nights in case he came back. It was a bit weird to come home after work and find a balaclava'd copper in my blacked out flat.